Arena maps out its one-year plan for lorcaserin

Arena Pharmaceuticals and its partners at Eisai have had a chance to review exactly what the FDA wants to see on their experimental weight drug.

Arena Pharmaceuticals ($ARNA) and its partners at Eisai have had a chance to review exactly what the FDA wants to see on their experimental weight drug and promise to have a complete response shipped over by the end of next year. But the news failed to impress investors, with the biotech's shares sagging close to 10 percent this morning.

Arena's lorcaserin was one of two obesity drugs that failed to make the cut--so far--at the FDA this fall. And with regulators zeroing in on its potential safety issues, a number of analysts have adopted a skeptical view of its chances in 2011. But after Orexigen's Contrave won an advisory vote recently, the chances for Vivus's Qnexa seemed to brighten considerably.

Last October's CRL asked for new data from a one-year study of obese and diabetic patients and asked Arena to come up with one or more independent experts to take a second look at tumor data to see if the agency's cancer worries can be addressed. In the event the FDA